Conventionally, there is a cellular mobile communication system applied to a traffic system in which a mobile station is a train, an automobile running on a highway, or the like. Since tracks of trains or traveling paths of automobiles are known in such a mobile communication system, it is possible to determine a base station capable of communicating with the mobile station on the basis of a position of the mobile station obtained by a positioning system or a travel distance from a reference position. That is, the mobile station can perform a handover depending on the position of the mobile station. In a case where the position of the handover by the mobile station is already determined, a handover procedure between the mobile station and the base station is simplified, so that the handover can be performed in a short time. Patent Literature 1 discloses a technique with which a mobile station switches connection destinations from a current base station to another base station when distance to the other base station becomes equal to or less than a preset threshold.